QB 51 
I.C35 
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A 1) 1) R ESS 



THE AMERICAN ASSOCIATION 



ADVANCEMENT OF SCIENCE, 



AUGUST, 1859. 



PROFESSOR ALEXIS CASWELL 



PUBLISHED FOR THE ASSOCIATION, 
BY JOSEPH LOVERINO, 

PERMANENT SECRETARY. 
1 8 59. 



ADDRESS 



THE AMERICAN ASSOCIATION 



FOR THE 



ADVANCEMENT OF SCIENCE, 



AUGUST, 185 9, 



BY 



PROFESSOR ALEXIS CASWELL 



/ 



<V 






PUBLISHED FOR THE ASSOCIATION, 



BY JOSEPH LOVERING, 

PERMANENT SECRETARY. 

185 9. 



c amb ridge; 
Allen and Farnham, Printers. 



ADDRESS 



PROFESSOR ALEXIS CASWELL, 



PRESIDENT OF THE AMERICAN ASSOCIATION FOR THE YEAR 1858, 



ON RETIRING PROM THE DUTIES OF PRESIDENT. 



Mr. President, and Gentlemen of the American Association 
for the Advancement of Science : — 

It sometimes happens that one finds himself in a position 
which requires an explanation, or even an apology. Such is 
my own case this evening. The duty which devolves upon 
me more properly belongs to another. Your Constitution pro- 
vides for a Retiring Address from your President. He be- 
comes, for the time being, your official adviser, — the exponent 
of your views. This is one of the objects contemplated in 
calling him to the presidency. Your Vice-President holds a 
somewhat different relation to the body, and may not, without 
seeming arrogance, take upon himself the special functions of 
his official superior. 

My own predilections and sense of fitness would have pre- 
cluded my appearance before you in this official capacity. 

1 



2 ADDRESS OF THE PRESIDENT 

Hitherto, on these occasions, you have listened to the accred- 
ited representatives and leaders of American science, each of 
whom might well apply to himself the motto, " Quorum mag- 
na pars fui." I am but an humble laborer in the ranks. But 
I am here at your command, which, having for its object the 
advancement of science, is not lightly to be set aside. I 
should be unworthy of the confidence which you have reposed 
in me did I not endeavor to comply with your wishes in giving 
to our proceedings that completeness which the constitution 
contemplates. But in doing this, if I shall fail to offer any 
thing worthy of your attention, I beg you to bear in mind that 
it is not a failure of my own seeking. When I have done 
what I can, I shall take shelter in a divided responsibility. 

Permitted to convene on this, our Thirteenth Annual Meet- 
ing, it is fit that we should, as a first duty, pay a passing trib- 
ute of respect to the memory of those who have left us. It is 
well that we should pause even in the grave and urgent pur- 
suits of life to ponder on its brevity. 

Since our last meeting, several who have been accustomed 
to participate in our proceedings, have ceased to be numbered 
with the living. Prof. Ira Young, of Dartmouth College ; Prof. 
William M. Mather, of the University of Ohio, and at the 
time of his death the acting President ; and Prof. Denison Olm- 
sted, of Yale College, have been borne to their long homes. 
They were all widely known in Academic circles. 

Prof. Young was born in the town of Lebanon, New Hamp- 
shire, May 23, 1801. His father was by trade a carpenter, 
which trade the son also followed till he had attained his ma- 
jority. He early manifested mechanical ingenuity and an 
ardent love of knowledge. On arriving at the age of twenty- 
one, he commenced a course of study preparatory to entering 
college ; which, with his diligence and ability, was soon com- 
pleted. He entered Dartmouth College, and, having completed 
the academic course, graduated with distinction in 1828. Like 
many distinguished graduates of our colleges, he defrayed the 
expenses of his education mainly by the fruits of his own in- 



OF THE ASSOCIATION. 



dustry. He was soon called to the post of Tutor in the col- 
lege, and after two years of service in that capacity, was 
elected to the Professorship of Natural Philosophy and Astrono- 
my, which chair he filled with marked ability and success, till 
the time of his death, Sept. 13, 1858, — a period of twenty-five 
years. He was a man of exact knowledge, of great firmness, 
of inflexible integrity, and of exemplary Christian piety. He 
was well versed in all the subjects pertaining to his department, 
and was, in the opinion of those most familiar with him and 
most competent to judge, an admirable teacher. He died in 
the fifty-eighth year of his age. 

Prof. Mather was a native of Middlesex county, in the State 
of Connecticut. The date of his birth has not fallen under 
my notice. His name appears in the list of graduates of the 
United States Military Academy, at West Point, for 1828. 
He entered the army, but in 1829 was appointed Assistant Pro- 
fessor of Chemistry, Mineralogy, and Geology in the Academy, 
and continued to discharge the duties of that post for a period 
of six years. He resigned his commission in the army in 1836, 
and was elected to the professorship of Chemistry in the Uni- 
versity of Louisiana, which place he held but for a short period. 
He was connected in succession with the geological surveys 
of the States of New York, Ohio, and Kentucky. His final 
report on the geology of the first district in New York was 
published in a large quarto volume in 1823. This is regarded 
as his most important original work, and in the opinion of 
competent judges, bears "honorable testimony to his ability 
and accuracy as an observer in this department of nature." * 
He also published valuable reports of his labors in connection 
with the surveys of Ohio and Kentucky. From 1847 to the 
time of his death, Feb. 29, 1859, he was Professor of Natural 
Sciences in the University of Ohio, and for some time previous 
to his death acting President of that institution. He was a 
valuable contributor for many years to the American Journal 

* American Journal of Science, Vol. XXVII. p. 452. 



4 ADDRESS OF THE PRESIDENT 

of Science, in the departments of Chemistry, Mineralogy, and 
Geology. 

For the facts connected with the life of Prof. Olmsted I am 
indebted mainly to a discourse commemorative of his life 
and services, delivered in the college chapel at New Haven, 
shortly after his death, by President Woolsey. 

From this it appears that he was born in East Hartford on 
the 18th of June, 1791. He was a descendant of James Olm- 
sted, one of the first settlers of the colony of Connecticut. 
Bereaved of his father while but an infant, his youthful train- 
ing was under the direction of his pious and most excellent 
mother. He gave early indications of a love of books, and 
diligently availed himself of such slender means of instruction 
as the common schools of the place and the moderate resources 
of his family could afford. With the aid and encouragement 
of a few friends who became interested in his youthful prom- 
ise, he prepared himself for admission to Yale College in 1809, 
where he was graduated with distinction in 1813. During 
his collegiate course he indicated no marked preference for any 
particular branch of study. If there was any department in 
which he might be said to be distinguished, it appears to have 
been that of literature. " He excelled in writing," says Presi- 
dent Woolsey, " and cultivated a taste for belles-lettres and 
poetry." On leaving college, he taught for a while a select 
school for boys, and was then appointed a tutor in the institution ; 
where, in addition to the duties of his tutorship, he commenced 
the study of theology, under the supervision of that distin- 
guished teacher and theologian, Dr. Timothy Dwight. During 
this same year, Mr. Olmsted was appointed Professor of Chem- 
istry in the University of North Carolina, the sciences of 
geology and mineralogy being included in the professorship. 
While connected with that university he was invited by the 
State to undertake a survey of its geology and mineral treas- 
ures. A report of these labors was published in 1824-5, un-. 
der the direction of the State Board of Agriculture. After a 
period of seven years' service at Chapel Hill, he accepted, in 



OF THE ASSOCIATION. 

1825, the appointment of Professor of Mathematics, Natural 
Philosophy, and Astronomy in his Alma Mater. For thirty-four 
years, with the utmost diligence and fidelity, he fulfilled the re- 
sponsible duties of this station, with the exception that the de- 
partment of Mathematics was after a few years constituted a 
separate professorship, and placed in other hands. It may be 
remarked in this connection, that his tastes and his early profes- 
sional studies, did not lead him to the cultivation of the higher 
branches of the Mathematics. Throughout the long period of 
his professional life he sustained the reputation of an excellent 
teacher, specially apt in the clear and skilful presentation of 
whatever subject he had occasion to treat before his classes. He 
w T as the author of several text-books for colleges, which have 
passed through many editions. He also gave to the public sev- 
eral popular compends of science, designed for more general use. 
His text-books for colleges were his Natural Philosophy 
and his Astronomy. In both of these works he has restricted 
himself to the more elementary portions of the sciences, and 
has employed exclusively the geometrical methods in distinc- 
tion from the analytical. It seems to have been with him 
through life a leading object to make science popular, and this 
perhaps determined him in the particular mode of presenting 
it, deeming the geometrical method, of the two, the more readily 
understood. However true this may be, — and for beginners 
it undoubtedly is true, — the calculus, since the time of New- 
ton, has been the great instrument for developing, in all their 
extent, the physico-mathematical sciences, and cannot be too 
strongly commended to those who would prepare themselves 
for independent and aggressive research. 

In addition to his scientific and more popular books, Prof. 
Olmsted was a very frequent contributor to the pages of the 
American Journal of Science and Art. He was also an early 
and efficient friend of popular education, and was among the 
first to urge the importance of normal schools for the educa- 
tion of teachers. 

The extraordinary shower of meteors during the night of 
1* 



b ADDRESS OF THE PRESIDENT 

Nov. 12, 1833, drew the attention of Prof. Olmsted to the 
investigation of that subject. After a very laborious inquiry, 
both historical and scientific, he came to the conclusion that 
these meteors were portions of the extreme parts of a nebulous 
body which revolves around the sun interior to that of the earth, 
but little inclined to the plane of the ecliptic ; having its aphe- 
lion near the earth's path, and having a periodic time of 182 
days nearly. * These researches attracted the attention of the 
public at home and abroad, and received the commendation of 
several of the most eminent astronomers of Europe. The 
explanation here given unites, perhaps, a larger number of 
suffrages than any other, and yet is hardly to be considered as 
one of the established facts of science. 

The elaborate memoir of Prof. Olmsted, entitled, " On the 
Recent Secular Period of the Aurora Borealis," published by 
the Smithsonian Institution, may justly be regarded as one of 
the most valuable papers which have been given to the public 
on the perplexed subject of the Northern Lights. 

Few men have been called to drink more deeply of the bit- 
ter cup of affliction than our deceased friend and associate. 
Between the years of 1844 and 1852, he buried four dutiful 
and promising sons, — all graduates of Yale College. Their 
mother had died before them. These heavy bereavements he 
bore with singular Christian fortitude and resignation. As a 
citizen, teacher, and friend, he was universally beloved. I 
should fail in doing justice to his memory did I not quote a 
single sentence, illustrative of his character, written a few days 
before his discease. " In view of the uncertain issue of this 
sickness," he writes, " I desire humbly to cast myself upon 
God, humbly to implore his forgiveness of my sins through 
Jesus Christ, and to express a cheerful hope that, should I be 
called away, it will be to my heavenly Father's house." 

We now pass to other considerations appropriate to this oc- 
casion. 

* Woolsey's Discourse, p. 17. 



OF THE ASSOCIATION. / 

It is not expected that this Address will take the form of a 
scientific paper. It embraces a wider scope and more varied 
topics. And yet it is hoped that it will not, on that account, 
be the less pertinent to the general purposes of our meeting. 

The object of this Association is the advancement of sci- 
ence. Here two things are implied : first, that science is an 
object worthy of our pursuit; and, secondly, that combined 
efforts are necessary to its progress. A few moments' consid- 
eration of these points may not be without interest. 

1. To say that science is worthy of our pursuit, may at 
first seem to be a mere waste of words, — the statement of a 
proposition to which every one assents. But what do we 
mean by science ? Is it the method of converting the products 
of the fields and forests into articles of commercial value? 
Does it specially embrace those labor-saving machines by 
which one man does the work of twenty or an hundred ? Is 
it chiefly found in the immense accumulation of mechanical 
force by which ponderous masses of iron and stone and tim- 
ber are handled and tossed about as if they were mere play- 
things in the hands of giants ? Certain it is that science has 
largely contributed to these results. But results like these by 
no means limit the value and range of science. These are ex- - * 

amples of its immediate -aMLily*- But it has claims to our c^t^x^y 
consideration beyond its immediate utility. The high and 
very just appreciation of what is termed practical and useful 
has, no doubt, in many instances, operated to the injury of 
what is termed speculative and theoretical. Nor is this singu- 
lar. The random speculations and the fallacious theories with 
which the world abounds, under the pretence of improvements 
and progress, have contributed in the general mind to depre- 
ciate all scientific results, I will not say, which are not suscep- 
tible of practicable applications (for of this we cannot judge), 
but which have not yet been applied to practice. There is 
everywhere a pressing demand for what is practical, and often 
a narrow utilitarianism, which looks with suspicion, and some- 
times with contempt, upon the profoundest speculations of 



8 ADDRESS OF THE PRESIDENT 

science, because they do not pay back to the laborer the wages of 
his hire in marketable value. The scientist, no less than the se- 
verest utilitarian, rejoices in every contribution of science to 
the arts, but he does not admit that the whole value of science 
is to be measured by any present applications. He puts in a 
demurrer to the conclusion that those portions of it are useless 
of which we do not now see the utility. The use may be be- 
yond our present sphere of vision, or, if coming within our cog- 
nizance, it may not admit of comparison with any standard of 
measure. Unlike the precious gem, which has an exchangea- 
ble but no intrinsic value, science bears no price in the market. 
It transcends all ideas of comparison and exchange. Its high 
utility lies in the breadth and dignity and sublime grandeur 
which it gives to the human mind. 

In the succession of geological strata, buried deep in the 
earth, with here and there an upheaval which brings them into 
view, as in the computed periods of astronomical perturba- 
tions, what vast cycles of time are brought within the grasp 
of the understanding? It is not merely the naked, isolated 
conception of an immense duration, but a distinct and orderly 
succession of events, which makes up the physical history of 
that duration. 

In the narrow sense of utility, it may be of little use to 
know what relation or fellowship exists between the two com- 
panions of a minute double star, — minute to us, but of vast 
intrinsic splendor ; — but what educated mind can be indiffer- 
ent to the fact that the identical law of gravity which deter- 
mines the fall of an apple, binds those stars to each other, and 
compels them, through vast cycles of time and almost bound- 
less space, to trace their elliptic orbits ? That, to our appre- 
hension, is the grandest law of nature. It controls the mate- 
rial universe, and heralds from sphere to sphere, in endless suc- 
cession, the order and harmony which emanate from the Cre- 
ator's will. It is thus, under the guidance of science, that our 
conceptions of law and order, of space and time, lead us to 
the Infinite. We look at the starry hosts, — myriads though 



OF THE ASSOCIATION. 



they be, — and ask, are there not more ? Is it in the lowest de- 
gree probable that the material world is bounded by the utmost 
limits of our telescopic vision? The universal dominion of 
the same law, the final stability which prevails over inevitable 
and endless perturbations, mark the universe as a system of 
exquisite and most perfect mechanism. It is the work of one 
Intelligence, and that one Intelligence is infinite. I cannot but 
think that the profoundest knowledge of nature leads, logi- 
cally, to this conclusion. And this is one of the grandest utili- 
ties of science. It raises the human mind to the intelligent 
contemplation of the Deity. 

But this is not all. The ministry of science stops not here. 
I go further and maintain that a profound knowledge of na- 
ture, in her laws and adaptations and vastness, puts us in pos- 
session of the truest and best means of weighing the evidence 
of a divine revelation, and suggests many analogies in its de- 
fence. I shall not hesitate, in this presence, to give utterance 
to my own profound conviction that all true science is in har- 
mony with the Bible, rightly interpreted. Any seeming dis- 
crepancy which baffles the resources of ingenuity to reconcile 
is but the varying ripple on the mighty swell of the ocean, 
whose exact form no power of analysis can express, and no 
skill of the pencil sketch. It is but the fleecy cloud which 
dims a little patch of the deep blue sky, or the smallest visible 
spot which can be discerned on the broad, blazing disc of the 
sun, which would not be seen at all but for the splendor of its 
surroundings. 

Science is not unfriendly to religion. True it is that some 
men, distinguished for science, have appeared to disregard the 
obligations of religion, and others have equally disregarded 
the obligations of morality. But science cannot be held re- 
sponsible, nor ought it to suffer reproach for delinquencies like 
these. Copernicus was a grave and devoted priest of religion, 
giving his energies, first to the cure of souls, then to the min- 
istrations of science. Kepler, it is said, seldom entered upon 
an important investigation without first seeking, by prayer, 



10 ADDRESS OF THE PRESIDENT 

the wisdom which is from above. Newton was a devout 
Christian, scarcely less distinguished for his piety than for his 
unrivalled power of mathematical analysis and his rare skill in 
experimental research. Examples like these, of which the an- 
nals of philosophy are richly stored, while they prove nothing in 
respect to religion, may well serve to exonerate science from 
the charge of infidel tendencies. 

I have adverted to this topic for the purpose of glancing at 
the higher ends of science, and specially for the purpose of re- 
lieving the fears of any who may look upon the bold and fear- 
less advance of physical investigations as ominous of evil to 
the interests of religion. We participate in no such fear. We 
wish explicitly to exonerate this Association from all suspicion 
of undermining, or in any^manner weakening, the foundations 
of that faith which an apostle says was once delivered to the 
saints. We cannot admit the opinion, that any progress in 
science will ever operate to the disparagement of that devout 
homage which we all owe to Him in whose hand our breath 
is and whose are all our ways. Science, on the contrary, lends 
its sanction and adds the weight of its authority to the sub- 
lime teachings of revelation. Such are its ends, over and be- 
yond its immediate practical utilities, and such are its claims 
upon our service. 

2. We may now say, that combined efforts are necessary to 
its further progress. 

The mathematical sciences grow by a development from 
within ; the physical mainly by accretions from without, To 
the progress of pure analysis it might seem that there was lit- 
tle opportunity for the cooperation of different minds, — that 
one master-spirit must lead the way, and all others must fol- 
low. The cooperation here is not by simultaneous, so much 
as by successive, labors. The ancient geometers laid the foun- 
dation ; the modern have built the superstructure. Each suc- 
cessive laborer has resumed the work where his predecessor 
left it. Each has added his link to the golden chain. And 
yet even here so varied and distinct are the fields of analytical 



OF THE ASSOCIATION. 11 

research, that the demand for labor is always fully equal to the 
supply. 

The physical sciences advance by observation, by the ac- 
cumulation of fact, by experimental research and induction. 
Here the simultaneous cooperation of many laborers is often 
indispensable. In the science of Meteorology, for example (if 
in its present state it can properly be called a science), what an 
accumulation of observations must be made, simultaneous, 
widely extended, and long continued, before the work of dis- 
cussion and critical analysis can hope to develop minutely the 
laws of atmospheric change. These changes, however seem- 
ingly capricious, are doubtless as much in accordance with 
fixed laws as the planetary orbits. But whether the compli- 
cated elements which enter into them ever can be grasped and 
reduced to form, so as to give to the science that completeness 
which belongs to Astronomy, may well be doubted. That re- 
sults most important to agriculture, to commerce, and to the 
sanitary condition of mankind may be reached, is no longer 
problematical. It may be regarded as one of the certainties 
of future progress. But these results must be based upon the 
comparison and discussion of a wide range of observation. 
Much is to be hoped in this respect from the system of obser- 
vations organized by the Smithsonian Institution in this coun- 
try, in connection with similar organizations in England, France, 
and Germany. The same extended cooperation is required 
for the advancement of Gfeology, Mineralogy, Terrestrial Mag- 
netism, Botany, Zoology, and indeed of all the departments of 
Natural History. 

What we want, then, and what we aim at, in this Associa- 
tion, is to render the scientific resources of the country availa- 
ble. The cooperative agencies are numberless. Every eye 
that can see, every ear that can hear, every hand that can re- 
cord, and every intellect that can analyze and combine, may 
contribute to the grand result. We invite the widest coopera- 
tion. The wisdom of this body will point out the most pro- 
ductive fields of labor, and, as far as possible, suggest the best 
methods of research. 



12 ADDRESS OF THE PRESIDENT 

But in order to gather around us, and bring into active co- 
operation the scientific talent of the country, we must work 
with a true devotion to science. By our practical wisdom, 
our friendly criticism, our impartial justice, our magnanimity 
and self-sacrifice, we must show that we deserve the confidence 
of an enlightened public. 

In glancing at the field before us, I must limit my remarks 
to a single department, — that of Astronomy, — to which my 
own attention has been more particularly given. 

It has long been the boast of Astronomy, that it is the oldest 
and most perfect of the sciences. But how can we predicate 
perfection of a science that is in a state of rapid advancement ? 
Astronomy at the present time must be regarded as one of the 
most progressive of the sciences. One or two illustrations of 
its progress will not be out of place. Tycho Brahe was a great 
astronomer. His magnificent observatory has a world wide 
celebrity. And yet it was an observatory without a telescope. 
Compare the pinnules and coarse graduations of his instru- 
ments with the refinements of modern telescopes, circles, and 
micrometers, and you have an impressive idea of progress. By 
a laborious comparison of Tycho's observations, Kepler arrived 
at the conclusion that the planets revolve in elliptical orbits. 
By the law of gravitation it is now shown that those elliptical 
orbits are subject to perpetual perturbations, and the minute 
changes which they must severally undergo for ages to come 
are pointed out with almost unerring precision. These per- 
turbations themselves become, in the hands of the physical 
astronomer, unequivocal exponents of the condition of the 
system. They open up new vistas into space, through which 
his far-reaching analysis catches the gleams of coming light. 
The discovery of the planet Neptune will ever constitute a 
brilliant epoch in the annals of Astronomy, and place the names 
of Leverrier and Adams in the foremost rank of geometers. 
The planet Uranus was known to be subject to slight irregu- 
larities of motion. Conjecture had for some time assigned the 
cause to be the attraction of an unknown planet. Analysis in 



OF THE ASSOCIATION. 13 

the hands of these geometers confirmed the existence of such 
planet, and pointed to its place in the far off depths of ether. 
And on turning the telescope to the spot, behold there it was. 
Such an achievement belongs to the. ninteenth century, and 
was scarcely possible at an earlier period. Without accurate 
measurements the irregularities of Uranus could not have been 
detected ; without that analysis, itself one of the noblest mon- 
uments of the human intellect, the place of the unknown 
planet could not have been conjectured. 

As a further illustration, let me refer to the recent labors of 
Hansen in perfecting the Lunar Tables. The irregularities of 
the moon's motions, owing to the perturbation of the sun and 
planets, have been the subject of perplexity and anxious in- 
quiry with astronomers from the time of Hipparchus. No 
tables could be constructed which would assign the moon's 
place with accuracy for any long period. So great was the 
difficulty of the problem that Euler despaired of ever being 
able to reduce the error in the computed place of that body, to 
any very narrow limits. Hansen undertook the reexamination 
of the Lunar Theory, as based upon the best modern observa- 
tions, and particularly upon those of the Greenwich Observa- 
tory. His profound knowledge of the theory of perturbations- 
enabled him to detect two inequalities of considerable magni- 
tude, due to the action of Venus ; which being incorporated 
in the tables relieves the subject almost entirely of embarrass- 
ment, and assigns the moon's place for any epoch with all the 
precision required by the present state of the science. 

With these improved tables, Professor Airy has been enabled 
to settle the long contested epochs of several memorable 
ancient eclipses ; as, for instance, those of Thales, and Agath- 
ocles, and that at Larissa ; and has thereby established several 
important points in ancient chronology beyond all reasonable 
doubt. A curious fact connected with one of these eclipses 
shows in what manner the light of science reflected backward 
sometimes illustrates the dark points of history in the remote 
past. I am tempted to refer to it. It is stated by Diodorus 

2 



14 ADDRESS OF THE PRESIDENT 

Siculus that the fleet of Agathocles, the tyrant of Sicily, was 
blockaded in the harbor of Syracuse, by the Carthaginians, 
with whom he was then at war. Shut up within narrow 
limits, and pressed on every side, he resolved on the bold and 
memorable project, then for the first time contemplated in the 
history of Carthaginian warfare, of "carrying the war into 
Africa." Under cover of the night, aided by many ingenious 
stratagems, he escaped from the harbor, and sailed for the 
African coast, pursued by the blockading fleet. Six days after 
his escape, having eluded the pursuit of the enemy, he landed 
at the " Quarries," burnt his ships, sacrificed to the gods, and 
commenced a campaign of conquest and slaughter which has 
few parallels in the history of warfare. An interesting account 
of it is given by Grote. On the day after the escape of 
Agathocles from Syracuse, " there was such an eclipse of the 
sun," says Diodorus, " that the day wholly put on the appear- 
ance of night, stars being seen everywhere." * History has left 
it uncertain when this memorable event occurred ; and it has 
been made a critical question whether Agathocles passed 
round on the north or on the south side of the island. Sin- 
gular as it may seem, the astronomical researches of Hansen 
and Airy have shown with more than historic certainty, that 
on the 15th of August, 309 before Christ, at six o'clock and forty 
minutes in the morning, Greenwich mean time, Agathocles 
witnessed a total eclipse of the sun, and must have been on the 
south side of Sicily. 

But in the present advanced state of astronomical science, 
what, it may be asked, remains for astronomers to do ? What 
new and noble achievements invite their toil ? It would not 
be easy, perhaps not possible, to enumerate all the unsolved 
problems of astronomy. Several subjects of great interest 
may, however, be mentioned, which await further investigation. 

(1) The true dimensions of the solar system, however 
much has been done in that direction, are by no means settled 

* As quoted by Prof. Airy, Phil. Trans. Vol. LXXI. p. 187. 



OF THE ASSOCIATION. 15 

with that exactness which precludes the desire of closer ap- 
proximation. The great primary problem, next to the size of 
the earth, is the distance of the sun. This has been pro- 
nounced by Airy to be the grandest problem in astronomy. I 
will not here detail the methods by which any error in the 
present determination may be eliminated or reduced. I shall 
refer to it again. With any correction in the sun's distance, 
all the planetary distances will take new value ; and with these 
corrected distances, it may be necessary to reconstruct the 
tables of all the older planets. Then there are the asteroids, 
now numbering, I think, fifty-five (55). A vast amount of 
labor is necessary to determine their exact orbits. Their mu- 
tual perturbations will demand and receive attention. Nor 
will the possibility of their ever having ' found a single body, |f'f?^>^^ 
broken in pieces by some violent shock of nature, be permitted 
to pass without severe scrutiny ; nor the other possibility of 
two or more of them being, by their mutual attractions, drawn 
together and forming a double planet. The physical constitu- 
tion of the planetary bodies, and especially that of the sun, 
presents questions of great interest, which it would be unphi- 
losophical to despair of being able to solve. The solar spots, 
of which the number has been very large during the present 
season, deserve, it would seem, to be scrutinized with the high- 
est powers of the telescope. The present theories respecting 
them are, by no means, so satisfactory as to preclude further and 
more thorough investigation. Such an inquiry would proba- 
bly determine more exactly than is now known, the time of 
the sun's rotation on his own axis. Whether it would throw 
any light upon the cause of their greatest and least abundance 
in periods of about eleven years, as discovered by Schwabd, 
time must determine. Do these spots occasion any sensible 
change in the solar radiation, and consequent change in the 
temperature and productions of the earth? Do they exist 
equally in all parts of the equatorial region ? Or are there 
special localities for the development of those immense tor- 
nadoes whose ravages we see in the blackened face of the sun ? 



16 ADDRESS OF THE PRESIDENT 

(2) Leaving our own planetary system, when, let us ask, 
will the department of cometary astronomy be exhausted? 
At any moment, these strange visitors may burst upon us in 
mild or terrific splendor, as the case may chance to be. What 
variety of form do they present, what tenuity and what rapid 
and prodigious diffusion of luminous matter, driven off as if 
by the impulse of solar light ? How soon the earth will come 
into collision with some one or more of the millions which 
are supposed to exist, and they swallow us, or we swallow 
them, none can tell. It requires evidently a special corps of 
observers, a scientific vanguard, to watch their movements 
and ward off. But, gravely, what are the internal forces which 
produce such immense diffusion of cometary matter in so 
short a time ? Do the portions of the tail driven off many 
millions of miles from the nucleus, ever return to it? Or do 
they remain suspended in mid ether, in a condition to be gath- 
ered up by the next one which sweeps along the sky ? 

(3) Sidereal astronomy is itself a subject of boundless ex- 
tent. With the aid of instruments of great refinement, many 
thousands of stars have been observed and their places deter- 
mined with great precision. But this is not, like the computa- 
tion of a table of logarithms, a work for all time. At no 
very distant epochs the entire sidereal heavens must be reex- 
amined. The stars are said to be fixed, but reexamination 
shows that very many of them are not fixed. They have mo- 
tions of their own — some greater, some less. What may be 
the result of the comparison of places, accurately determined 
for very distant epochs, we cannot predict. If the catalogue 
of Hipparchus, transmitted to us by Ptolemy, containing up- 
wards of a thousand stars, could have been based upon the 
precise determination of modern instruments, we might now, 
looking upon the exact changes of two thousand years, be able 
to predict the further changes for many thousands of years to 
come. We might have under our immediate inspection, as in 
the case of the planet Neptune, a small portion of the orbit, 
which would enable us to describe the whole. In that case, 



OF THE ASSOCIATION. 17 

to the contemplation of the astronomer, how grand and solemn 
would now be the order and movement of the starry hosts ! 
To temporary inspection they are all fixed ; — to the eye of a 
thousand years all are in motion, — all pursuing their appointed 
orbits to be circled only in millions of years. 

(4) How much is yet to be known of the three thousand 
and upward of double stars already catalogued! The peri- 
odic times, the positions and forms of the orbits of several, 
have already been proximately determined. In one instance, 
at least, that of Gamma Virginis, we have seen one star 
occulted by the other. It is said that in 1836 no telescope in 
Europe could separate the two stars. They are now quite 
wide apart. Continued attention to this class of objects 
will undoubtedly reward the inquiry with most interesting 
results. 

(5) But what shall we say of variable and periodic, of new 
and lost stars? What a boundless field of observation, in- 
quiry, and conjecture, does this subject open before us ! — a field 
scarcely yet entered upon, but one which is, no doubt, destined 
to yield the richest harvest to the labors of future astronomers. 
What are the physical conditions which determine Algol, in 
the short space of three and a half hours, to change from a 
star of the second, to one of the fourth, magnitude, remain at 
its minimum brightness fifteen minutes, and then in three and 
a half hours more return to its former magnitude, and go through 
the same changes continuously in a period of little more than 
two days ? What shall we think of Mira Ceti, which remains 
completely invisible to the naked eye for five months, then in- 
creases for three months, when it attains to the brightness of a 
star of the second magnitude; retaining this brightness for 
about two weeks, it again decreases for three months and dis- 
appears as before ? It occupies about eleven months in pass- 
ing through these changes. A still greater wonder is Eta Ar- 
gus, which changes at irregular intervals from a star of the 
fourth, to one of the first magnitude, second only to Sirius in 
brightness. The whole number of variable stars which have 

2* 



18 ADDRESS OF THE PRESIDENT 

been subjected to a more or less careful examination, is from 
thirty to forty. Hind has remarked that the prevailing color 
among them is of a reddish hue ; and in several instances, at 
least, during the period of least brightness they are surrounded 
by a hazy or nebulous light. These facts seem to point to 
some common characteristic. They indicate like physical 
conditions. " The whole subject of variable stars," says Her- 
schel, " is a branch of practical astronomy which has been too 
little followed up, — it holds out a sure promise of rich discov- 
ery." It is also a branch in which amateur astronomers, with 
moderate instrumental means, or even with good eyes alone, 
can labor to advantage. 

(6.) But we have not yet reached the widest field of inquiry. 
With telescopes of good definition and great power of illumi- 
nation, the nebulae present objects of interest which are hardly 
second to any others. The results furnished by the great re- 
flector of Lord Rosse encourage the hope of most decided pro- 
gress in this branch of astronomy. Whether the nebulae are 
all groups of stars capable of being resolved, or in some cases 
immense diffusion of luminous matter in the slow process of 
condensation, — worlds undergoing a formative process, — 
they are alike wonderful to contemplate. 

Such is a mere glance at the unexplored regions of Astron- 
omy. 

It is now time to ask, What may American astronomers be 
justly expected to do in advancing this, the noblest of sciences? 
We may best answer this question by looking at what they 
have done. In adverting to this topic it will be my endeavor 
not to transcend the limits of modesty and truth. I think it 
will appear from the educational and scientific history of 
the country, that scientific investigations, and especially 
astronomical pursuits, have always been held in high esti- 
mation among us. In proof of this I may allude to obser- 
vations made at the last two transits of Venus. It is well 
known that Prof. Winthrop of Harvard College, visited New- 
foundland in 1761, to observe the transit which occurred on 



OF THE ASSOCIATION. 19 

the 5th of June of that year. It is not, perhaps, so well known 
that the " Province Sloop " was fitted out at the public expense 
to convey himself and his party to the place of observation. 
Elaborate preparations were made in different parts of the 
country to observe the transit of June 3d, 1769. Private mu- 
nificence in the purchase of suitable instruments, and the 
cooperation of public bodies, bear honorable testimony to the 
enlightened zeal which animated the friends of science at that 
time. The observations of Rittenhouse and his associates, in 
Philadelphia, of Winthrop in Cambridge, and West in Provi- 
dence, rendered important aid in determining the problem of 
the sun's parallax. 

But while an honorable appreciation of astronomical science 
has been perpetuated among us, strange as it may seem, until 
within a very recent period, we have wanted the instrumental 
means and appliances necessary to prosecute it on independent 
grounds. So recently as 1840 we had done almost nothing in 
the way of astronomical o xp c rimonts i There were at that 
time in possession of the coast survey, several fine instruments 
for the determination of latitude, for transits and for moon- 
culminations ; and the reports of that department show how 
well they were used. Yale College had an altitude and 
azimuth refractor, by Dolland, of ten feet focal length, and five 
inch object glass. This at the time of its reception in 1830 
was much the largest refractor in the country. Its mounting 
in the tower of one of the college edifices was by no means 
equal to its optical power. Williams College had a Herschel- 
ian reflector of ten feet focal length, equatorially mounted 
and a very good transit instrument. Hudson Observatory, in 
Ohio, had an equatorial refractor of four inches aperture. 
The fine telescope of the Philadelphia Observatory — an equa- 
torial of eight feet focal length and six inch object glass, by 
Merz and Mahler, of Munich — was received in the autumn 
of 1840. Its erection marks an era in the history of our astro- 
nomical instruments. In optical power, and in the fineness of 
its graduations, it was quite superior to any thing which we 



20 ADDRESS OF THE PRESIDENT 

then had. It was, moreover, the first of the fine German tel- 
escopes imported into the country. "When I have mentioned 
these instruments I have given a summary of our means of 
astronomical observation at the close of 1840. We had many 
other telescopes, that were useful in observing eclipses, occul- 
tations, and transits, and which afforded interesting views of 
many of the heavenly bodies, but none with high optical pow- 
ers and accurate graduations, for the exact determination of 
the elements of position. 

What have we done in this department within the last 
twenty years ? I will not occupy your time with a history of 
American observatories, which must be familiar to the most of 
you. Suffice it to say, that we have now several not unwor- 
thy of comparison with some of the old and world-renowned 
observatories of Europe. Astronomical instruments have two 
objects in view; the one is the increase of optical power, 
the other is the exact determination of position. The one 
class of instruments scrutinizes the celestial bodies, and shows 
us what they are, the other tells us where they are. 

As it respects optical power, we have at least six telescopes 
in use, which are entitled to high rank. The first in size is the 
great Munich Refractor at Harvard University, of twenty-two 
and a half feet focal length and fifteen inch object glass, made 
after the same models as the great refractor of the Russian 
observatory at Pulkova. These two instruments stand alone. 
Among refractors they have no equals. The results given by 
the Cambridge instrument in researches upon the nebulae, upon 
the ring of Saturn, in the discovery of the eighth satellite of 
that planet, and upon the nucleus of the brilliant comet of 1858, 
fully attest its power. The Munich telescope at Ann Arbor, 
has an object glass of thirteen inches aperture. The telescope 
at the observatory of Hamilton College, in the State of New 
York, made by Spencer, has an object glass of thirteen and a 
half inches, and one at the private observatory of Mr. 
Rutherford, in the city of New York, made by Fitz, has 
also an object glass of thirteen and a half inches. These 



OF THE ASSOCIATION. 21 

three instruments, two of them of American workmanship, 
are reputed to be of excellent quality. They are all equa- 
torially mounted. The refractor of the Cincinnati Observa- 
tory, with a twelve inch object glass, and that of Washing- 
ton Observatory, with an object glass of nine and six tenths 
inches aperture, have both rendered good service to astron- 
omy, and have acquired a high reputation for excellence. 
They are both from Munich. The instrument at Washington 
is of the same size as that which was used by Struve" for 
many years, with such signal success, at Dorpat. 

For the coordinates of position, the right ascension and 
declination, we have mounted and in use, six meridian circles 
of the most refined construction, reading off to a single second 
of arc, and with the microscopes attached, descending practi- 
cally to tenths of seconds, while the chronometers give the 
time to intervals much less than the tenths of seconds. These 
circles are at the observatories of Cambridge, Washington, 
Georgetown, West Point, Ann Arbor, and Albany. The last- 
named instrument, constructed under the special supervision 
of the late director of the Dudley Observatory, Dr. B. A. 
Gould, contains improvements which, it is believed, place it 
second to no other of the kind which has ever been made. It 
will remain a proud monument of the ability and practical 
skill of the director. It is understood that the other instru- 
mental equipments of this observatory will be of the highest 
order. And it is hoped that an institution so nobly conceived 
and so auspiciously commenced, will, notwithstanding the 
adversity which has unhappily befallen it, and checked its 
progress, yet fulfil the distinguished promise of its inaugu- 
ration. 

In addition to these, there are in the possession of collegi- 
ate institutions and in the hands of amateur astronomers, 
I think, not less than twenty instruments, which are ca- 
pable, under favorable circumstances, of showing the princi- 
pal division in the ring of Saturn, and of opening double stars 
from V to 2" apart. Many of these are equatorially mounted, 



22 ADDRESS OF THE PRESIDENT 

and from time to time will be able to furnish most valuable 
contributions to astronomy. 

It will thus be seen, that with our public appreciation of 
science, and the princely munificence of private citizens, we 
have in the short space of twenty years furnished ourselves 
with the means of embarking with advantage upon the most 
refined and difficult branches of practical astronomy. In ad- 
dition to this, we may say, without undue self-esteem, that we 
have many observers among us who have attained to great 
practical skill in observation ; observers who have studied the 
theory of errors in construction and adjustment and observa- 
tion, and have made themselves proficients in the best method 
of detecting and eliminating them. The published proceed- 
ings of this Association bear honorable testimony to the pro- 
found ability with which the most difficult problems of celestial 
mechanics have been discussed before us. The volumes of 
the Washington and the Cambridge Observatories speak for 
themselves. They show that American observatories may be 
relied upon for the most accurate determinations. The astro- 
nomical expedition to Chili, which had for its object a new 
and independent determination of the solar parallax, reflects 
great credit upon the scientific enterprise and ability of Lieut. 
Gillis. The elaborate computations made by Dr. Gould, give 
for that important element a result extremely near to the re- 
ceived value as based upon the transit of Venus in 1769. 
And, what is pertinent to our present purpose, the new deter- 
mination (8". 5) is based alone upon American observations. 

It is understood that the observatories of Cincinnati and 
West Point contain records of high value which have not 
been made public. The astronomical and geodetic labors of 
the United States Coast Survey, including the method of lon- 
gitudes by the electric telegraph, show consummate skill in the 
conduct of difficult researches, and reflect the highest honor 
upon the scientific character of our country. We think it 
may be said with safety, that none of the great geodetic en- 
terprises of modern times, beginning with Picard's, has been 



OF THE ASSOCIATION. 23 

more thoroughly accurate than our own. The application of 
the electric telegraph to transit observations, known among 
the astronomers of Europe as " The American Method" — 
because conceived and perfected by American genius — is 
undoubtedly one of the greatest improvements in practical 
astronomy known to the history of the science. It enables 
the observer to do in a given time quadruple the work which 
was possible without it, and with nearly quadruple accuracy. 
The American Nautical Almanac, representing numerically 
the latest and highest improvements in planetary astronomy, 
shows what progress we have made in the difficult art of com- 
putation. I call it a difficult art because in a work of five or 
six hundred pages of closely printed figures, the intention and 
the expectation is that it shall be free from errors. To achieve 
this is a work of the utmost difficulty. It is a record of the 
ability of American computers, and in some respects a record 
of American science. I may extend this last remark to the 
xlstronomical Journal, edited by Dr. Gould, which, in the main, 
presents American astronomical science in its most refined, 
practical, and analytic forms. 

In the manufacture of the requisite qualities of glass for 
telescopes and in the construction of instruments of the very 
largest descriptions, we have not yet attained to the excellence 
of our older neighbors on the other side of the Atlantic. But 
who shall say that even that is a forbidden field to the genius 
or American artisans ? Who shall say that Guina/d and n, 
Frauenhofer will not find their proud rivals in American work- 
shops to share with them the glory of perfecting the noblest 
of instruments, the astronomical telescope ? The eminent 
success of Spencer, Fitz, and Clark, in telescopes of large size, 
to say the least, gives us substantial ground to hope that with 
due encouragement on the part of the public, we shall erelong 
in this department be able to meet the severest demands of ad- 
vancing science. 

There is still another and higher department of astronomy 
which, in some directions, forms the solitary basis of further 



24 ADDRESS OP THE PRESIDENT 

progress. Without it, facts may be observed and accumu- 
lated, but the remote and hidden laws of which they are con- 
sequences and ultimate exponents, can never be reached. I 
refer to that higher mathematical analysis which seizes the act- 
ual conditions of the system and demonstrates from them the 
laws which must exist, or which takes the laws as we now 
have them and demonstrates what must be the condition of 
the system at any time to come. A higher and nobler func- 
tion of the human mind than this we can hardly conceive, be- 
low that of paying its devout homage to the Supreme Archi- 
tect of these countless worlds above us. And here the name 
of Bowditch stands as a proud monument of American sci- 
ence. The profoundest problems of the Mecanique Celeste 
did not evade his searching scrutiny. But the name of Bow- 
ditch stands not alone. That of the lamented Walker is not 
unworthily associated with it. Other names there are, which 
delicacy forbids me to mention in this presence. Posterity, 
with even-handed justice and pious care, will assign them an 
honorable place among the great geometers of the age. 

I have before alluded to the problem of the sun's distance, 
It is well known that the determination of that important ele- 
ment rests almost exclusively upon the observations on the 
transit of Venus in 1769. It is also known that the reliable 
observations on that occasion were fewer than could have been 
desired, and, strange to say, some which were given to the 
world were of doubtful authenticity. And we may add that 
however valuable the results obtained from observations on 
Mars in opposition, and Venus in conjunction, the next tran- 
sit of Venus in 1874 is regarded as the surest means of veri- 
fying or correcting the previous determination of the sun's 
parallax. The astronomer royal of England has already 
called the attention of astronomers to this problem, and says 
that it is not too soon to begin the preparation for so impor- 
tant an event. He looks to the astronomers of the United 
States to take a leading part in the enterprise, and adverts to 
the peculiar advantage which will result from connecting 



OF THE ASSOCIATION. 25 

together a series of stations covering a great extent of country 
by that wonderful auxiliary to science, the electric telegraph. 

To all the foregoing, I may add that the application of the 
art of photography to astronomy, now regarded as another 
" wonderful auxiliary," is due to American genius. The late 
director of the Cambridge Observatory, the lamented Bond, 
was the first to make the application, and show its practical 
importance. That sun-painting art, which delineates so quickly 
and so truthfully the features of the " human face divine," 
delineates with equal facility and equal precision the features 
of the sun, moon, and planets. The relative position of 
double stars and groups of stars is given with an accuracy 
scarcely inferior to the best rnicrometric measurements. 

From the facts which have now been stated, the question 
again recurs, What may justly be expected from American as- 
tronomers in advancing their chosen science ? But the facts 
themselves emphatically answer the question ; — and that 
answer is, Much every way. 

The material equipments are at hand, or if not at hand, will 
soon be furnished when solicited by the spirit of devotion and 
earnest progress. True, we have not the princely and govern- 
mental patronage which gives vitality and strength to many 
scientific establishments of Europe. But we have what few 
other countries can boast to the same extent, an enlightened 
public sentiment, a jus*t appreciation of the dignity and impor- 
tance of science, penetrating every portion of our community, 
and commanding not only the wealth of merchant princes, but 
the wages of hardy industry, to achieve the object of scientific 
culture. With a dependence like this, which is elastic, buoy- 
ant, versatile, and which readily adapts itself to the exigencies 
of pressure and demand, we need not shrink from the noblest 
enterprise. We have skilful observers, we have ready and 
practised computers, we have mathematicians who will be re- 
sponsible for any contributions which analysis can make to 
the common progress. Such, gentlemen, is our position; such 
is the responsibility which rests upon us. 

3 



26 ADDRESS OF THE PRESIDENT OP THE ASSOCIATION. 

It remains for us to aid and encourage each other and show 
what may be done by a generous devotion to a noble cause. It 
may be that some of us will have occasion to profit by the pre- 
cept of the Hebrew preacher, " If the iron be blunt and he do 
not whet the edge, then must he put to more strength." With 
the strength of firm resolve and the whetted edge of diligence, 
we may enter with good hopes upon the task before us. Our 
united efforts will surely not be fruitless. 



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